We used it for our trip in Oct. We liked it, but I wouldnt recomend using for everyday of your trip. Its a great way to get in the most rides, but it does sort of make you rush past things and miss a bit of the magic. I recomend using it for one day to really get the rides done. Then spend the rest of trip just taking things as they come along, reriding favorites, watching shows etc.
If nothing else, pay the $15-16 and play with the program. It will give you a good idea of what time of day to hit various rides and what to expect for lines while you are there.
(sign up for the 3 month plan if you're only making the one trip over the period of a year). We didn't even stick to the schedule the entire time, but it sure helped us to plan our days, make the best use of fastpasses, and helped us to "think outside the box" when manouvering through crowds. The website (once you have signed up) also gives you some very good tips on parades, early entries, etc. that we made good use of. I think the longest we stood in line was 25 minutes, and that was at Minnie's House in Toontown and Ridemax estimated that we'd be in line that long! For under $20 US, it's a fun tool to play with prior to your trip and for us, it actually made it stress-free. For Ridemax to work the best for you, plan on being in line well before those gates open in the morning! Have a great time! 
